A harvesting device for a machine harvesting fruits comprising of a straddle carrier frame having a vertical median plane of symmetry; two shaker assemblies which are mounted face-to-face on the frame on respective opposite sites of the vertical median plane of symmetry and for shaking the fruit-bearing trees or shrubs passing between the two shaker assemblies to detach the fruits, berries or the like therefrom, each shaker assembly comprising: drive mechanism; a plurality of vertically spaced shaker members, each shaker member comprising a flexible material rod that extends substantially horizontally and has a curved shape, each rod having a first end that is connected to the drive mechanism, a median portion that is adapted to engage the fruit-bearing trees or shrubs to shake them, and a second end that is connected to the frame by a connecting link that extends substantially horizontally and perpendicularly to said vertical median plane of symmetry so that, in operation, said second end of the rod is maintained at a substantially constant distance from said vertical median plane of symmetry.
Harvesting devices of the type described hereinabove are known in the art. Such harvesting devices are described in the documents FR 2 605 487, 2 789 262 and 2 813 493, for example. In these prior art harvesting devices, and in the corresponding harvesting machines that have been made commercially available, each connecting link comprises a rigid metal component that is connected firstly to the second end of the corresponding flexible shaker rod and secondly to the frame by articulated connections. The articulated connection between the link and the flexible shaker rod usually comprises a ball joint and the articulated connection between the link and the frame usually comprises two ball bearings or roller bearings. Given that, in service, the links connecting the flexible shaker rods to the frame are continually subjected to an oscillatory movement and operate in an environment laden with dust and/or plant debris, the ball joints and the ball or roller bearings of the connecting links have to be lubricated frequently, around every eight hours of service. Given that each harvesting machine may comprise up to fourteen or even more shaker rods, and thus fourteen connecting links, and consequently fourteen ball joints and twenty-eight ball or roller bearings, it is clear that lubrication is a lengthy and complicated operation. Furthermore, the operator of the machine must take care not to get grease or oil onto components which, in service, come into contact with the fruit-bearing trees or bushes, and in particular with vines, as this could have harmful effects on the vinification process.
It has also become apparent that, in operation, the inertia of the connecting links, which comprise relatively heavy rigid metal members, may interfere with the movement of the flexible shaker rods.
Also known in the art (FR 2 641 158, FIG. 6) is a harvesting device in which each shaker rod has a rear end connected to the frame by a leaf spring, one end of which is connected to the rear end of the shaker rod by an articulated connection and the other end of which is connected to the frame by a rigid connection. However, in this case, the leaf spring is parallel to the vertical median plane of symmetry of the harvesting device and is prestressed in such a manner as to confer differential flexibility on the assembly comprising the shaker rod and the leaf spring. To be more precise, the leaf spring opposes or brakes the movement of the shaker rod when that movement is outward relative to the vertical median plane of symmetry of the harvesting device, whereas it does not oppose, or even assists, the movement of the shaker rod when that movement is toward said vertical median plane of symmetry. Although the leaf spring also provides a connection between the shaker rod and the frame, it has neither the same disposition nor the same function as the connecting link of the harvesting device to which the present invention relates, in the sense that the leaf spring does not maintain the rear end of the shaker rod at a substantially constant distance from said vertical median plane of symmetry. To the contrary, with the harvesting device shown in FIG. 6 of the document FR 2 641 158, in service, the rear end of the shaker rod moves to-and-fro in a direction substantially perpendicular to the vertical median plane of symmetry, with an amplitude equal or substantially equal to the amplitude of the to-and-fro movement of the median active part of the shaker rods.